Obesity is becoming increasingly widespread in the developed world, and the medical dangers of obesity are well known. Non-invasive treatment, by diet and exercise, is difficult for many patients to maintain. Surgical treatments include surgically reducing the usable volume of the stomach. Such surgery is effective but expensive, and, like any major surgery, has risks, especially for patients whose obesity has caused other health problems. Less extreme methods include wiring the jaws closed, and planting an expandable balloon in the stomach, either surgically or endoscopically. But these procedures can be uncomfortable, and also carry risks.
U.S. Pat. No. 5,032,415, to Battista, describes pills containing a swelling material, such as a compressed mass of cellulose fibers, which are swallowed and swell in the stomach, suppressing appetite. U.S. Pat. No. 6,271,278, to Park et al, describes superabsorbent material which is encapsulated in gelatin, and swallowed, swelling in the stomach once the gelatin dissolves.
U.S. Pat. No. 6,548,083, to Wong et al, and U.S. Pat. No. 6,488,962, to Berner et al, describe material which is swallowed and swells in the stomach, not for suppressing appetite, but in order to release drugs into the stomach gradually, over a period as long as 24 hours.
U.S. Pat. No. 6,627,206, to Lloyd, describes small magnetic cubes or tetrahedrons which are swallowed, a few at a time, in capsules. After the capsules dissolve in the stomach, the magnets self-assemble into a space-filling mass, which suppresses appetite.
U.S. Pat. No. 4,812,315, to Tarabishi, describes a balloon, folded in accordion fashion, and swallowed in a capsule. The balloon contains sodium bicarbonate, and once the capsule dissolves in the stomach, the balloon absorbs hydrochloric acid which reacts with the sodium bicarbonate, producing carbon dioxide which expands the balloon, suppressing appetite.
U.S. Pat. No. 4,607,618, to Angelchik, describes a hollow, semi-rigid device, which is collapsed and inserted into the stomach through an endoscopic feeding tube. In the stomach, the device spontaneously recovers its original shape, expanding, and suppresses appetite. Similar devices, in some cases inserted into the stomach directly through the esophagus, are described in U.S. Pat. No. 5,868,141, to Ellias, U.S. Pat. No. 4,648,383, U.S. Pat. No. 5,306,300, and U.S. Pat. No. 6,755,869.
U.S. Pat. No. 6,740,121 describes a stent, made of a bio-absorbable material, which is placed in the duodenum, limiting the uptake of food passing through it, until it degrades and passes from the body.
All of the devices described above have the potential disadvantage that they remain in the stomach for a long time, much longer than food normally remains in the stomach, and they can block the pylorus, or, if partially broken up, could potentially block the intestines. In some of these devices, there is also the potential danger that they could expand (or swell, for amorphous materials) prematurely in the esophagus, if the capsules dissolve before they reach the stomach for some reason.
As described in http://www.medid.com/bips_features.html, Medical ID Products produces x-ray opaque Barium Impregnated Polyethylene Spheres (BIPS) to help diagnose blockages and motility problems in the stomachs and intestines of cats and dogs. The spheres are packed in gelatin capsules which are swallowed whole and dissolve in the animal's stomach, or the loose spheres are mixed in with food which is fed to the animal.
All of the above patents and publications are incorporated herein by reference.